1. Field of the Invention
This invention relates to the cutting of vegetation, and more particularly, it relates to the cutting of vegetation using a flexible non-metallic line extending from a rotating head into a cutting plane.
2. Description of the Prior Art
For many centuries man has struggled in the cutting of vegetation, using knives, scythes, clippers, and various other metal cutting blades. These manual devices in many cases are very awkward to use and produce serious strains upon the user's body. For example, the scythe is an implement consisting of a long, curved single-edged metal blade with a long bent handle having two handgrips to be grasped by the user. The scythe is used in a sideways swinging motion for mowing, reaping and other cutting. The scythe was a substantial improvement over plain knives, hooks and sickles in that the user was able to use both hands in making left and right substantially equal swings during the cutting operation. However, the swing to the left consumed the most energy of the work in cutting vegetation. Nevertheless, there was a balance of rythmic movement making the scythe superior as a cutting instrument to the sickle and other single-bladed, single-handed devices.
Invention of the reaper-type harvesting machinery during the mid-nineteeth century freed most of the workers from the great physical labors of manual cutting instruments for harvesting crops. As a result, the hand-held cutting devices, such as sickles and shears, were retained for trimming, edging and grass cutting in small areas. The twentieth century created a large group of homeowners doing grass cutting, trimming, clipping and the like in their own yards. During this period, the gasoline and electrically powered lawnmowers, trimmers and edgers replaced the earlier manual cutting device. These powered devices employed rotating metal cutting blades which could inflict serious and terrible injury to the user upon accidental contact. Nearly one hundred thousand users of metal-bladed power equipment are injured annually.
In about 1960 there was developed in Europe a trimmer-edger unit employing a flexible polymeric line extending from a rotating head for cutting vegetation. The unit did not work properly because of several defects in structure and operating perameters. In the United States of America during the 1970's, there were patented practical vegetation cutting devices using flexible non-metallic lines carried upon a rotating head. The devices are shown in U.S. Pat. Nos. 3,708,967, 3,826,068, and 3,859,776. These patented devices have met outstanding success worldwide in the marketplace. One reason for this success is that they are probably the safest electric or gasoline powered tools yet invented for vegetation cutting, edging and trimming operations.
The patents 3,708,967 and 3,826,068 disclose one embodiment of the unique apparatus driven by a gasoline engine, for rotating a head carrying one or more flexible non-metallic lines which are extended in a cutting plane for removal of vegetation. These powered devices are relatively large and are held by the user using a two-handed grip much like the historic scythe. The user also has an over-the-shoulder strap to help balance these devices while cutting vegetation. The two-handed grip is provided by a U-shaped handle secured at its center point to the support tube of the apparatus. The handgrips extend upwardly on the handle. The operator grasps the upstanding handle grips with his elbows bent but his hands extending in front of his body. As a result, the user swings his body at the waist in order to move the cutting head sideways or laterally through the vegetation during the cutting operation. Unfortunately, the handle is a handicap since the user loses some of the balanced swinging motion by foot movement available in the centuries-old scythe.
Many powered trimming, edging and cutting devices have been proposed which include various forms of two-handed grips with less than optimum desired characteristics. Namely, the operator must extend his arms directly in front of him; thus, his swings to left and right are not equal and comfortable while using these devices.
The scythe appears natural in rythmic movement to a user who has dancing abilities. More particularly, a dancer finds the left (cutting) swing of the scythe to be natural. However, the right (return) swing of the scythe is uncomfortable, since the scythe must swing towards the right leg which is slightly forward of his body. Preferably, the dancer would have both arms at a comfortable side-by-side position, make equal left and right swings of the scythe, or other tool, in comfortable movements, and balance his weight on both feet. These principles of a dancer in comfortable movements have been carried forward into arranging a novel handle member for motor-powered flexible-line cutting devices such as described in the afore-mentioned patents.